An Equal Channel Angle Drawing Method for Efficient and Continuous Preparation of Ultra-fine-grained Pure Titanium at Room Temperature

Abstract

The invention provides an equal-channel corner drawing method for efficiently and continuously preparing ultra-fine grain pure titanium at an indoor temperature. The method is achieved through an equal-channel corner drawing die composed of four modules A, B, C and D. The method comprises the following steps: taking a pure titanium bar or plate as a starting material, and manufacturing the equal-channel corner drawing die according to the cross section shape and the dimension of the starting material after annealing; polishing the blank and coating the surface of the blank and the surface of an equal-channel corner channel preformed by the four modules with a lubricating agent; putting the blank into the equal-channel corner channel, formed by the four modules, with an included angle of 90degrees or 110 degrees, then putting on a drawing machine, controlling the drawing speed to be 2 to 100 mm / s so as to enable the blank to pass through the equal-channel corner channel at a constant speed, removing the head and the tail of a drawn piece after each pass of drawing, rotating the drawn piece by an angle Theta clockwise or anticlockwise, then putting on the equal-channel corner channel for continued drawing again, and obtaining the ultra-fine grain pure titanium after 2 to 12 passes of drawing.

Description

technical field [0001] The invention belongs to the technical field of ultrafine-grain material processing, and in particular relates to an equal-channel corner drawing method for efficiently and continuously preparing ultrafine-grain pure titanium at room temperature. Background technique [0002] Pure titanium (Ti) and its alloys have good corrosion resistance, high specific strength, good biocompatibility, non-toxic, non-magnetic, low elastic modulus, fatigue resistance, poor electrical and thermal conductivity, etc., and are widely used in surgical implant materials. For example, artificial joints, bone plate screws and dental implants are widely used in fields such as artificial joints, and become the main development direction of medical metal materials in the future. Ti-6A1-4V alloy is widely used clinically at present. Studies have shown that the Al and V metal ions released by long-term corrosion in the human body are harmful to the human nervous system and respirat...

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Problems solved by technology

[0003] Metallic pure Ti has a close-packed hexagonal structure, less slip system at room temperature, poor plasticity, and problems such as difficulty in severe plastic deformation at low temperature and deformation cracking.

The large-scale plastic deformation methods of pure Ti that have been studied more include equal-diameter angular extrusion (such as patents CN101580924A, CN101624690A, CN103343303A, CN103981472A, CN104690496A, CN103252377A, CN105821360A), high-pressure torsion (such as patents CN102234732A, CN10202A), and multi-directional forging. (such as patent CN103320734A), etc., most of them have some problems, the most important of which are the limited size of the prepared materials and low production efficiency. In addition, there are also high mold requirements, high cost, uneven organization, and low material utilization. Disadvantages, especially for hard-to-deform materials with a close-packed hexagonal structure, the forming temperature is high (>200°C) and the deformation speed is slow (0.025-2.5mm / s), which has always been the difficulty that the large plastic deformation method needs to break through

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